A pair of scientists at California Pacific Medical Center in San Francisco have found that a compound derived from marijuana could stop metastasis in many kinds of aggressive cancer, potentially altering the fatality of the disease forever.

“It took us about 20 years of research to figure this out, but we are very excited,” said Pierre Desprez, one of the scientists behind the discovery, to The Huffington Post. “We want to get started with trials as soon as possible.”

The Daily Beast first reported on the finding, which has already undergone both laboratory and animal testing, and is awaiting permission for clinical trials in humans.

Desprez, a molecular biologist, spent decades studying ID-1, the gene that causes cancer to spread. Meanwhile, fellow researcher Sean McAllister was studying the effects of Cannabidiol, or CBD, a non-toxic, non-psychoactive chemical compound found in the cannabis plant. Finally, the pair collaborated, combining CBD and cells containing high levels of ID-1 in a petri dish.

“What we found was that his Cannabidiol could essentially ‘turn off’ the ID-1,” Desprez told HuffPost. The cells stopped spreading and returned to normal.

“We likely would not have found this on our own,” he added. “That’s why collaboration is so essential to scientific discovery.”

Desprez and McAllister first published a paper about the finding in 2007. Since then, their team has found that CBD works both in the lab and in animals. And now, they’ve found even more good news.

“We started by researching breast cancer,” said Desprez. “But now we’ve found that Cannabidiol works with many kinds of aggressive cancers–brain, prostate–any kind in which these high levels of ID-1 are present.”